1. Field of the Invention
The present invention relates to an image projection apparatus.
2. Description of the Related Art
Conventionally, projectors of a digital light processing (DLP) (registered trademark) system widely employ a method of varying a waveform of electric power that is supplied to a light source emitting light having brightness in accordance with the electric power that is supplied depending on video image modes in order to change the brightness and color among the video image modes. For example, in a video image mode called high-brightness mode requiring high brightness, a method in which electric power that is supplied to the light source increases at a timing at which a transparent segment (transparent color filter) of a color wheel as a transmissive disc segmented into a plurality of colors is irradiated with light from the light source and the electric power that is supplied to the light source decreases at a timing at which a blue segment thereof is irradiated with the light from the light source can be used.
For example, Japanese Patent Application Laid-open No. 2014-41359 discloses a method in which brightness of a light source for each of filters in a projector using a color wheel having red, blue, green, and transparent filters is changed so as to increase brightness of white light of the projector or increase intensities of red light and blue light instead of decreasing the brightness of the white light.
However, There is no conventional projector capable of switching a mode in which brightness of a projected image is maximum and a mode in which the brightness of the projected image is minimum, and even a structure for providing such projector has not been known.